I'd start with the question: where do you want them to go? Windowing systems generally don't have a 'limbo' where windows can live without being displayable, and that probably isn't what you want, either.
Do you want them all to auto-minimize? You can probably get that. But it starts with answering the question.
I could imagine a tiling window manager like sway having a "temporarily gone" pseudo-workspace that holds windows that were on another monitor until you plug it back in or pull them to another workspace. Or to remember that workspaces 1, 3, and 5 were on another monitor recently, and to put them back there when you plug back in.
Sway does the latter. When you have multiple displays, every workspace gets assigned to a display. When you remove a display, those workspaces move onto a remaining display, but, importantly, every window stays on the workspace it was on, so you don't get shuffling and rearranging windows. When you plug that display back in, those workspaces go back to that display. I get that there's no "perfect" way to handle this situation, but the way Sway does it is so much more simple and predictable than Gnome or Windows.
If it's the same problem I've had, I feel the pain!
On a laptop, reconfiguring to use monitors as and when you connect/disconnect them can be great.
However, I'm often on a PC with a fixed multi-monitor setup. The situation where one monitor is briefly out is transient. But some windowing systems decide to permanently erase all your painfully eked out settings at the drop of a hat.
The correct behavior in this particular case is actually just to do nothing, the fact that a monitor seems to have gone away should just be ignored. (Because it didn't go away, really. Maybe I'm just messing with it for a sec, or it's a different brand and turns on/off a few seconds after the others)
[IIRC on KDE you can prevent auto-reconfiguration by turning Kscreen OFF ]
Or even cheaper, there are little HDMI EDID emulation dongles. That said, you end up with windows staying on unreachable displays, so it's not always the best solution.
Do you want them all to auto-minimize? You can probably get that. But it starts with answering the question.